Neuropsychological studies of brain-damaged patients suggest that the right hemisphere (RH) is specialized for behavioral functions that collectively contribute to social interaction and bonding. In particular, patients with right hemisphere damage (RHD) are reported to have abnormalities in emotional facial expression and prosody, attention, arousal, and mood. While these social-emotional disorders of the right hemisphere have ben documented in laboratory assessment, there has been little research examining their effects on natural behavior and interpersonal relations. Given the importance of social cognition in daily interaction, these disorders may prove more disabling for RHD patients and their families than previously thought. The specific aims of this study are a.) to document the extent and evolution of social-emotional and cognitive dysfunction in our population of RHD patients using laboratory measures that have been proven reliable in previous research; and b.) to examine the effects of right versus left hemisphere damage and associated neurobehavioral disorders (documented in laboratory assessment) on spontaneous social interaction and marital relations during the 18 month follow-up period. We will compare patients with unilateral right and left hemisphere infarcts and age and sex-matched control patients with orthopedic disease on laboratory measures of paralinguistic, neuropsychological, and affective function and correlate these results with subjects' performance in studies of spontaneous social interaction. First, judges will rate facial expression and prosody in videotapes of interviews with patients and their spouses. Second, the spouse of each patient will observe and record patient social behavior at regular intervals over the 18 month follow-up period. We will also examine mood and perceptions of marital satisfaction in spouses as a function of presence and side of lesion in the patient. This research will contribute to basic knowledge of the brain regions involved in social behavior, as well as provide clinicians and caregivers with information regarding the effects of these impairments on interpersonal relations during both the acute and chronic phases. In the longterm, this research should contribute to the management of social-emotional and marital disturbance resulting from localized brain damage.